<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>v-once</title>
    <script src="Vue.js"></script>
</head>

<body>
    <div id="app">
        <input type="text" v-model="msg">
        <p v-once>你输入:{{ msg }}</p>
    </div>
    <script type="text/javascript">
    let app = new Vue({
        el: "#app",
        data: {
            msg: '我是钢铁侠, 大家好!'
        }
    })
    </script>
</body>

</html>